With the development of optical technology and semiconductor technology, flat panel displays such as liquid crystal display (LCD) and organic light Emitting Diode (OLED) have the advantages of lightness, low energy consumption, fast response speed and good color purity, high contrast and other characteristics, and occupy a dominant position in the display field.
In order to ensure the display quality, the display device will be tested at the factory, to test the electrical performance of the device product through screen lighting test. For example, through an external power supply, a 3.3V voltage is applied to the display screen as a logic input voltage VDD of a printed circuit board (PCB), to test the display effect.
During the test, it is required to ensure that the logic input voltage VDD is constant. However, when the displayed frame is switched, since load from the display screen is changed while the voltage of the external power supply is constant, the current will change, which inevitably results in change of the logic input voltage VDD. Since the external power supply voltage is converted to 3.3V by an adapter board, and then supplied to the PCB as the logic input voltage VDD, and during the conversion, the adapter board and an adapter cable will inevitably consume a part of the voltage, the logic input voltage VDD actually supplied to the PCB will be lower than 3.3V. Moreover, with the switching of the displayed frame, the heavier the load of the frame is, the greater the voltage drop will occur on the adapter board and the adapter cable, and thus the lower the logic input voltage VDD to the PCB will be.
In the related art, each time the displayed frame is switched, it is necessary to connect the test point of the logic input voltage VDD with a multimeter, and at the meantime, manually adjust the voltage of the external power supply such that the logic input voltage VDD remains constant, which results in significant inconvenience for the screen lighting test.
It is to be noted that the information disclosed in the above-mentioned background section is for the purpose of reinforcing the understanding of the background of the present disclosure and may therefore include information that does not constitute related art known to those of ordinary skill in the art.